1. 27 1月, 2015 1 次提交
  2. 06 12月, 2014 4 次提交
    • A
      samples: bpf: large eBPF program in C · fbe33108
      Alexei Starovoitov 提交于
      sockex2_kern.c is purposefully large eBPF program in C.
      llvm compiles ~200 lines of C code into ~300 eBPF instructions.
      
      It's similar to __skb_flow_dissect() to demonstrate that complex packet parsing
      can be done by eBPF.
      Then it uses (struct flow_keys)->dst IP address (or hash of ipv6 dst) to keep
      stats of number of packets per IP.
      User space loads eBPF program, attaches it to loopback interface and prints
      dest_ip->#packets stats every second.
      
      Usage:
      $sudo samples/bpf/sockex2
      ip 127.0.0.1 count 19
      ip 127.0.0.1 count 178115
      ip 127.0.0.1 count 369437
      ip 127.0.0.1 count 559841
      ip 127.0.0.1 count 750539
      Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      fbe33108
    • A
      samples: bpf: trivial eBPF program in C · a8085782
      Alexei Starovoitov 提交于
      this example does the same task as previous socket example
      in assembler, but this one does it in C.
      
      eBPF program in kernel does:
          /* assume that packet is IPv4, load one byte of IP->proto */
          int index = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol));
          long *value;
      
          value = bpf_map_lookup_elem(&my_map, &index);
          if (value)
              __sync_fetch_and_add(value, 1);
      
      Corresponding user space reads map[tcp], map[udp], map[icmp]
      and prints protocol stats every second
      Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a8085782
    • A
      samples: bpf: elf_bpf file loader · 249b812d
      Alexei Starovoitov 提交于
      simple .o parser and loader using BPF syscall.
      .o is a standard ELF generated by LLVM backend
      
      It parses elf file compiled by llvm .c->.o
      - parses 'maps' section and creates maps via BPF syscall
      - parses 'license' section and passes it to syscall
      - parses elf relocations for BPF maps and adjusts BPF_LD_IMM64 insns
        by storing map_fd into insn->imm and marking such insns as BPF_PSEUDO_MAP_FD
      - loads eBPF programs via BPF syscall
      
      One ELF file can contain multiple BPF programs.
      
      int load_bpf_file(char *path);
      populates prog_fd[] and map_fd[] with FDs received from bpf syscall
      
      bpf_helpers.h - helper functions available to eBPF programs written in C
      Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      249b812d
    • A
      samples: bpf: example of stateful socket filtering · 03f4723e
      Alexei Starovoitov 提交于
      this socket filter example does:
      - creates arraymap in kernel with key 4 bytes and value 8 bytes
      
      - loads eBPF program which assumes that packet is IPv4 and loads one byte of
        IP->proto from the packet and uses it as a key in a map
      
        r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)];
        *(u32*)(fp - 4) = r0;
        value = bpf_map_lookup_elem(map_fd, fp - 4);
        if (value)
             (*(u64*)value) += 1;
      
      - attaches this program to raw socket
      
      - every second user space reads map[IPPROTO_TCP], map[IPPROTO_UDP], map[IPPROTO_ICMP]
        to see how many packets of given protocol were seen on loopback interface
      
      Usage:
      $sudo samples/bpf/sock_example
      TCP 0 UDP 0 ICMP 0 packets
      TCP 187600 UDP 0 ICMP 4 packets
      TCP 376504 UDP 0 ICMP 8 packets
      TCP 563116 UDP 0 ICMP 12 packets
      TCP 753144 UDP 0 ICMP 16 packets
      Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      03f4723e
  3. 19 11月, 2014 2 次提交
  4. 31 10月, 2014 1 次提交
  5. 22 10月, 2014 1 次提交
  6. 02 10月, 2014 1 次提交
  7. 27 9月, 2014 1 次提交
    • A
      bpf: mini eBPF library, test stubs and verifier testsuite · 3c731eba
      Alexei Starovoitov 提交于
      1.
      the library includes a trivial set of BPF syscall wrappers:
      int bpf_create_map(int key_size, int value_size, int max_entries);
      int bpf_update_elem(int fd, void *key, void *value);
      int bpf_lookup_elem(int fd, void *key, void *value);
      int bpf_delete_elem(int fd, void *key);
      int bpf_get_next_key(int fd, void *key, void *next_key);
      int bpf_prog_load(enum bpf_prog_type prog_type,
      		  const struct sock_filter_int *insns, int insn_len,
      		  const char *license);
      bpf_prog_load() stores verifier log into global bpf_log_buf[] array
      
      and BPF_*() macros to build instructions
      
      2.
      test stubs configure eBPF infra with 'unspec' map and program types.
      These are fake types used by user space testsuite only.
      
      3.
      verifier tests valid and invalid programs and expects predefined
      error log messages from kernel.
      40 tests so far.
      
      $ sudo ./test_verifier
       #0 add+sub+mul OK
       #1 unreachable OK
       #2 unreachable2 OK
       #3 out of range jump OK
       #4 out of range jump2 OK
       #5 test1 ld_imm64 OK
       ...
      Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3c731eba